Chemistey Ex 2
Which of the following statements correctly describe formal charges and the skeletal arrangement of atoms in a Lewis structure? Select all that apply.
A structure in which nonzero formal charges are small is preferred to a structure in which they are large. A structure in which all formal charges are zero is preferred to a structure containing nonzero formal charges.
Select all the statements that correctly describe the five basic electron-domain geometries.
A system with three electron domains will have a trigonal planar electron-domain arrangement. An octahedral geometry indicates that there are six electron domains.
A compound has the empirical formula CH2O. What are the possible options for the molecular formula of this compound? Select all that apply.
C6H12O6 CH2O C2H4O2
Using the modern periodic table, select the two elements whose chemical properties you would expect to be similar.
Ca Mg
Which of the following options correctly describe the NH2-CH=O structure? Select all that apply.
Carbon will have a trigonal planar molecular geometry. Nitrogen will have a trigonal pyramidal molecular geometry.
Order the steps for drawing a correct Lewis structure for a molecule, beginning with the first.
Count complete place if necessary
How many electrons are in the valence shell of the central atom of ICl3Cl3?
10
Which of the following is the correct ground-state electron configuration for gallium (Ga; Z = 31)?
1s22s22p63s23p64s23d104p1
The molecular formula of a compound having an empirical formula NH2 (ℳ = 32.05 g/mol) is N _________ H ______________
2 4
The correct formula for the compound dichlorine pentoxide is Cl _______ O __________
2 5
A ball-and-stick model of the molecule serine is shown here. The molecular formula for this compound is given by C _________ H ___________ N ____________O___________.
3 7 1 3
In the molecule KrBr2 there are electron domains surrounding the central Kr atom; bonding pair(s) and lone pair(s). The molecular geometry around the central atom is therefore .
5 2 3 linear
Which intermolecular forces are exhibited between molecules of the compound shown? Select all that apply.
Dipole-dipole forces Dispersion forces
Which of the following statements correctly describe dispersion or London forces? Select all that apply.
Dispersion forces are a weak attraction between temporary dipoles. All covalent compounds exhibit dispersion forces.
Which of the following statements correctly describe the relationship between the electron configuration of an element and its position on the periodic table? Select all that apply.
Elements that are in the same group will have the same outer electron configuration. The highest occupied orbital for a Se atom is a 4p orbital.
Select all the statements that correctly describe how to determine the molecular shape of a species using VSEPR.
If unshared electron pairs are present, the molecular geometry will differ from the electron-domain geometry. The total number of shared and unshared electron pairs around the central atom gives the electron-domain geometry. Use the molecular formula to draw the Lewis structure.
Select all the statements that correctly describe the arrangement of lone pairs in systems with 5 and 6 electron domains.
In a trigonal bipyramidal system lone pairs prefer to occupy equatorial positions. If there are two lone pairs in an octahedral system they will be located opposite each other.
Which of the following statements correctly defines intermolecular forces?
Intermolecular forces are the weak forces of attraction found between the individual molecules of a molecular covalent substance.
Which of the following statements correctly describe ionic bonding? Select all that apply.
Ionic bonding involves the transfer of electrons from the metal to the nonmetal. An ionic bond is the electrostatic attraction between two oppositely charged ions.
Which of the following options correctly defines resonance structures?
Lewis structures for the same species that differ in the placement of electrons
What characteristics do elements in the same group have in common? Select all that that apply.
Main group elements in the same group have the same number of valence electrons. Elements in the same group have similar chemical properties.
Which of the following statements correctly describe how to calculate a molecular or formula mass for a compound? (Recall that a subscript of "1" is assumed)
The formula/molecular mass is derived from the sum of the masses of all atoms of the component elements. The atomic mass of a cation or anion is the same as the mass of the neutral element. In a formula such as Ca(NO3)2, all subscripts of atoms in parentheses must be multiplied by 2.
Select all the pieces of information that are necessary to calculate the mass % of an element in a given compound.
The molecular or formula mass of the compound The formula of the compound The number of atoms of the element in a molecule or formula unit of the compound
Which of the following statements correctly describe different categories of electrons? Select all that apply.
Valence electrons are the outermost electrons of an atom. For main group elements, the group number is also the number of valence electrons. Ca has two valence electrons.
A
central atom in structure
The ionic compound CrCl3 is correctly named _____.
chromium(III) chloride
Elements such as Na and K are in the same __________ on the periodic table. These elements have similar chemical properties because they have the same number of ___________ electrons.
column valence
Most covalently bonded substances consist of individual separate molecules. Each individual molecule is held together by means of strong bonds between the atoms. In addition, there are weak forces of attraction between the individual molecules, called forces.
covalent intermolecular
In general, electronegativity ______ as atomic size increases because a shared electron pair is closer to the nucleus of a smaller atom, which therefore attracts these electrons ______ strongly. Thus, electronegativity tends to ______ from left to right across a period of the periodic table and tends to ______ down a group.
decreases, more, increase, decrease
Rank the sublevels for a particular principal energy level in order of decreasing energy for a many-electron atom. Place the lowest energy sublevel at the bottom of the list.
f d P s
The larger a molecule or atom, the _____ the number of electrons and the _____ polarizable it will generally be. The strength of the dispersion forces for a particular substance therefore generally _____ as molar mass increases, providing molecules of similar shape are compared.
greater; more; increases
The Lewis structure for the cyanide ion is shown. The formal charge on the C atom is equal to _____ and the formal charge on the N atom is equal to _____.
-1; 0
For a many-electron atom, which of the following sublevels has the highest energy?
3d
What is the mass percent of oxygen in aluminum oxide (Al2O3)?
47.08%
True or false: A bond between O and H within any molecule is called a hydrogen bond.
False
True or false: All of the electrons in a many-electron atom can participate in covalent bonding.
False
Which of the following statements correctly describe a molecular formula? Select all that apply.
Subscripts in the molecular formula indicate the number of atoms of each element present in a molecule of the compound. The molecular formula CH4 represents a molecule that contains 1 carbon atom and 4 hydrogen atoms.
Which electrons are shown in a Lewis structure?
The valence electrons of all atoms in a molecule
The BrO3- ion is named bromate. What is the name of the oxoacid with the formula HBrO3?
bromic acid
The attraction between an ion and a nearby polar molecule is called an ion -
dipole ionic
formula shows the exact number of atoms of each element in one molecule of compound.
molecular
Hund's rule states that when a sublevel contains several orbitals of equal energy, ____________________ electron(s) must be placed in each orbital before electrons are _________________________.
one Paired
Which of the following is the correct name for Sr(NO3)2⋅4H2O?
strontium nitrate tetrahydrate
B
terminal atom
109.5o
tetrahedral
90o and 120o
trigonal bipyramidal
Which of the following statements are part of the proper calculation of the mass % of O in acetic acid (CH3COOH)? Select all that apply.
% O = 53.29% The mass of oxygen atoms in a mole of acetic acid is 32.00 g. The molar mass of acetic acid is 60.05 g/mol.
Which of the following Lewis dot symbols correctly represent each element? Select all that apply.
(a) B (c) S (e) H
Which of the following Lewis dot symbols correctly represent each element?
(b) C (c) Cl (e) N
The formula mass of K2CO3 is equal to _____.
138.21 amu
CCl CH20 SF6 KrF2
153.8 g/mol 30.03 g/mol 146.1 g/mol 121.8 g/mol
Which structure shown is the correct Lewis structure for XeF4?
B
Which of the following structures are NOT valid resonance forms for the sulfite ion, SO32-?
B C
How is a monatomic main group cation properly named?
By adding the word ion to the name of the element
Select the correct Lewis structure for the molecule NO.
C
Which of the following statements correctly describe the "normal" bonding pattern for a neutral atom of each element, assuming that the octet rule is obeyed? (See Sec. 5.2) Select all that apply.
C forms four covalent bonds. F forms a single covalent bond. H forms one covalent bond and is generally not found as a central atom in covalent species.
Select all the statements that correctly describe electronegativity.
Electronegativity describes the relative ability of an atom in a covalent bond to attract the shared electron pair(s). Electronegativity is a relative quantity.
Select all the polyprotic acids.
H3PO4 H2SO4
Which of the following acids is named correctly as an acid?
HBr: hydrobromic acid
Using the modern periodic table, select the element whose chemical properties you would expect to be similar to potassium, K.
Na
Which element will have similar chemical properties to an element with Z = 7?
P
Which of the following statements correctly describe the rules for naming oxoacids? Select all that apply.
The acid derived from the chlorite anion would be called chlorous acid. The names of oxoacids are related to the names of the oxoanions from which they are derived. The acid derived from the bromate anion would be called bromic acid.
main-group cations
The ion charge equals the group number.
Which of the following statements correctly describe molar mass? Select all that apply.
The molar mass is the mass in grams per mole of the substance. The periodic table can be used to calculate the molar mass of any substance.
Which of the following is NOT involved in determining the empirical formula of a compound from mass percent data?
The molar mass of the compound
Which statement about naming cations of main group metals is correct?
When a metal forms a cation, the word ion is added to the name, without changing the name of the metal.
P2 and P4 are ______________ of phosphorous, two distinct forms of the same element.
allotropes
The bond formed between two nonmetals, which are usually very similar in their tendency to lose or gain electrons, is a(n) _____ bond. This bond involves the _____ of one or more electron pairs between the two atoms.
covalent, sharing
Orbitals that are of equal energy may be referred to as
degenerate
Refer to the boiling point graph shown. H2O, NH3, and HF have much
higher hydrogen strong energy
A species will be nonpolar overall
if individual bond dipoles cancel.
A species will be polar overall
if individual bond dipoles do not cancel.
Place the following compounds in order of increasing strength of their intermolecular forces, with the weakest at the top of the list. These compounds have approximately equal molecular masses.
2CH3 OCH3 OH COOH
Certain molecules are electron deficient, having fewer than ________ electrons around the central atom. Elements that commonly form electron deficient compounds are beryllium and _____________.
8 B
How many grams of KMnO4 correspond to 3.13 × 1022 formula units of KMnO4? Avogadro's number is 6.022 × 1023.
8.21 g of KMnO4
Which of the following compounds exhibit hydrogen bonding between their molecules? Select all that apply.
A B E
Which of the following statements correctly defines a molecule?
A molecule is an independent structure consisting of two or more atoms chemically bonded together.
Which statement correctly explains how polarizability affects intermolecular forces?
A more polarizable molecule experiences stronger dispersion forces and therefore stronger intermolecular forces overall.
Select the statements that correctly describe naming an oxoanion. Select all that apply.
An oxoanion containing two fewer oxygen atoms than the -ate ion is called the hypo...ite ion. An oxoanion containing one more oxygen atom than the -ate ion will have the prefix per- added.
When drawing Lewis structures it is useful to recall the "normal" bonding patterns of common elements (Sec. 5.2). Match each element with the number of covalent bonds the neutral atom usually has if the octet rule is obeyed. Instructions
C---4 N---3 O---2 F---1
Match each compound with the correct mass % of hydrogen (H).
C6H6 ---- 7.74% CH3OH ---- 12.6% CH2O------ 6.71%
Which of the following compounds would experience the strongest overall intermolecular forces?
CBr4
Correctly associate each molar mass with its compound.
CCl4 ----- 153.8 g/mol CH2O ---- 30.03 g/mol SF6 ------- 146.1 g/mol KrF2------- 121.8 g/mol
If you calculate the mass of one entity of each of the following species, for which would you be calculating the molecular mass rather than the formula mass? Select all that apply.
CH2Cl2 PCl5
What is the chemical formula of the molecular compound whose ball-and-stick model is shown?
CHCl3
Select all the statements that correctly describe multiple bonds.
Carbon frequently forms multiple bonds. Bond strength increases with the number of electron pairs shared between two atoms. A multiple bond arises when two atoms share two or more electron pairs.
Which of the following elements, when covalently bonded, commonly have fewer than an octet of electrons with a formal charge of zero? Select all that apply.
Boron Beryllium
Which of the following statements correctly describe how to determine whether a given molecule is polar or nonpolar? Select all that apply.
For a molecule that has polar bonds, the molecular geometry must be known in order to predict the overall polarity. If a molecule contains no dipole moments across any bonds it will be nonpolar. If the individual bond dipoles cancel, the molecule is nonpolar.
Which of the following statements correctly defines formal charge?
Formal charge compares the electrons associated with an isolated atom to the electrons associated with the atom in a covalent species.
Which of the following compounds has the largest molar mass?
H2SO4
Pure covalent
Electrons are being shared equally between atoms.
Polar covalent
Electrons are being shared unequally between atoms.
Which of the following statements correctly describe how an orbital diagram is constructed? Select all that apply.
Electrons are placed by filling lower energy levels first. Orbitals may be listed horizontally or vertically. An individual orbital is represented by a box, circle, or line.
Which of the following statements correctly describe the Aufbau principle? Select all that apply.
Electrons are placed successively in orbitals, starting with the lowest energy orbital available. According to this principle the electron configuration of any element is determined by building it up in steps.
Ionic
Electrons have been transferred from one atom to another.
True or false: Any molecule in which all of the bonds are identical will be nonpolar.
False
Which molecule(s) contain(s) an odd number of valence electrons? Select all that apply.
OH NO2 NO
Which statement correctly defines the bond length of a covalent bond?
The distance between the nuclei of the two covalently bonded atoms
NH3 is ____________ and H2O is _______________
ammonia water
Molecular geometry is specified for a central atom in a structure. A "central" atom is _____.
any atom that is bonded to two or more other atoms
A molecule is an independent structure composed of two or more atoms chemically _____________ together. A molecule composed of two atoms of the same element is called a homonuclear _____________ molecule.
bonded diatomic
The molecular shape of a species, which is the arrangement of the bonded atoms around the central atom, is determined not only by the number of electron domains that join the atoms, but by the number of electron domains as well, since these electrons also occupy space.
bonding nonbonding
The compound Cu2O is correctly named ______.
copper(I) oxide
The term molecular mass can only be applied to a(n) _________________ compound since __________ compounds do not consist of molecules. The correct term in this case is _____________ mass.
covalent ionic formula
Which one of the following options gives the correct procedure to calculate the number of moles of a substance given the mass of a sample?
mass/molar x mass
A condensed electron configuration includes the element symbol of the _____ gas that is _____ to the relevant element in square brackets, followed by the configuration of the energy level being filled.
noble; prior
Which of the following provides the correct mathematical operation to convert the number of atoms of a sample to the number of moles?
number of atoms/ avogrados number
A chemical bond in which electrons are shared unequally between two atoms is called a ____________ ____________ bond.
polar covalent
An atom or molecule that contains an odd number of valence electrons is known as a free
radical
In a multi-electron atom, repulsions between electrons prevent valence electrons from "experiencing" the full positive charge of the nucleus. This repulsion is known as ______.
shielding
Repulsions between electrons in a many-electron atom results in a phenomenon known as _________________ which leads to the electrons "experiencing" a lower _________________ nuclear charge.
shielding effective
What is the correct systematic name for the compound Na2CO3?
sodium carbonate
In a Lewis structure of a molecule, only the ____________________ electrons are shown.
valence
In a many-electron atom, only the electrons at the ______ level will participate in covalent bonding.
valence
Which type of electrons are best at shielding a 3p electron?
2p
CH3F
Dipole-dipole forces
Resonance structures are Lewis structures that have the same relative placement of _____ but a different arrangement of _____.
atoms; electrons
Select all the lettered options that correspond to equatorial positions in the image shown.
b c d
Which of the marked positions would a single lone pair prefer to occupy? Select all that apply.
b c d
Which of the following marked bonds are hydrogen bonds? Select all that apply.
b d
In a given chemical compound, the component _____ are present in _____ proportions by mass, regardless of the source of the compound.
elements; fixed
A 5-electron domain system (shown) has two different types of positions for electron domains. The three positions marked "1" form a trigonal plane about the central atom and are called positions, while the two positions marked "2" are positions.
equatorial axial
The Pauli ________________ principle guarantees that no two electrons in the same atom have the same quantum number description. This means that the maximum number of electrons that can be accommodated by any orbital is __________________
exclusion Two
Elements that do not obey the octet rule because they have more than eight valence electrons are said to have an ______________ valence shell. This is only possible for elements that have available _________________ orbitals, which are the elements found from period ___________ of the periodic table onward.
expanded d 3
Individual bond dipoles will cancel
for a species that has identical bonds and a symmetrical geometry.
Individual bond dipoles will not cancel
for a species with an unsymmetrical geometry.
Formula and molecular masses are calculated using the chemical _____________ of the relevant compound, and the atomic masses obtained from the _________ table. The _______________ of the atomic masses in the correct proportions gives the formula or molecular mass of the compound.
formula periodic sum
Each element in a given compound comprises a fixed percent by __________ of the compound. This observation is summarized by the law of definite __________.
mass composition
Hund's rule states the most stable configuration occurs when electrons occupy degenerate orbitals in such a way as to _____ the number of electrons with the same spin.
maximize
The ________ __________ of a substance is the mass per mole of a substance, in units of g/mol
molar mass
The ________________ ____________________ of a substance is the mass per mole of a substance, in units of g/mol.
molar mass
The _____ formula of a compound is an integer multiple of the _____ formula.
molecular; empirical
Which one of the following options gives the correct procedure to calculate the mass of a substance given the number of moles?
moles × molar mass
An acid that has only one ionizable proton is termed ____________, whereas an acid with two or more ionizable protons is termed ____________.
monoprotic polyprotic
In general, a lone pair repels bonding electron pairs _____ than bonding pairs repel each other. A lone pair will therefore _____ the bond angle between bonding pairs. A double bond has a similar effect.
more, decrease
Which of the following statements correctly describe compounds? Select all that apply.
A compound contains a fixed number of atoms in its formula. A compound has a fixed mass ratio of its components. A compound is a pure substance.
Which of the following statements about Lewis structures are correct?
A covalent bond is represented as a line or as dots between atoms. A Lewis structure shows the number of covalent bonds between bonded atoms. Lone pair electrons are represented as pairs of dots.
Arrange the necessary steps in order for finding the molecular formula of an unknown compound from mass percent data. Place the first step at the top of the list. Instructions
Assume Convert Derive Divide Multiply
Which of the following molecules have a central atom with an incomplete octet? Select all that apply.
B
Which of the following statements correctly describe how to name acids? Select all that apply.
Binary acids are named using the prefix hydro-. The name of a binary acid contains the nonmetal root with the suffix -ic.
A particular hydrocarbon (a compound consisting only of C and H) contains 14.4% H by mass. If the molar mass of the compound is 85. ± 2 g/mol, what is the molecular formula?
C6H12
Select all the statements that correctly describe dipole-dipole attractions.
For two compounds of similar molar mass, the greater the molecular dipole moment, the stronger the dipole-dipole attraction. These are the forces of attraction between two polar molecules.
Select all statements that correctly describe formal charge.
Formal charge can be used to determine the most plausible Lewis structure for a given compound. Formal charge is the comparison of an atom's associated electrons with its isolated valence electrons.
Place the steps in order for calculating the molar mass of nitrogen gas, starting with the first step at the top of the list.
Identify that Multiply Report
Greek numerical prefixes are used to indicate the number of atoms of a particular element present in a molecular compound. Four atoms of the same element will be named with the prefix _____________ , while the prefix _________________ is used to indicate two atoms of the same element.
tetra di
C3H8
Dispersion forces
Organize the steps for determining molecular shape in the correct order, starting with the first step at the top of the list. Instructions
use count determine electron determine molecular
A Lewis dot symbol consists of an element's symbol, surrounded by dots that represent its __________ electrons
valence
Select all the correct statements regarding ion-dipole interactions.
Ion-dipole interactions only occur in mixtures. An ion-dipole interaction exists between an ion and a polar molecule. The magnitude of ion-dipole interactions is inversely proportional to the size of the polar molecule. Ion-dipole interactions are responsible for the solubility of ionic compounds in aqueous solutions.
A ___________________________ structure represents the covalent bonds and nonbonding electrons for a given chemical compound.
Lewis
An elemental symbol surrounded by dots that represent that atom's valence electrons is known as a(n) _____.
Lewis dot symbol
Which of the following formulas for ionic compounds are written correctly? Select all that apply.
Mg3(PO4)2 CaCO3 NaNO3
Select all the statements that correctly explain why bond angles in molecules containing lone pairs or multiple bonds may be different than the VSEPR ideal.
Multiple bonds repel more strongly than single bonds that results in compression in adjacent bond angles. Lone pairs exert greater repulsion that causes compression in adjacent bond angles. Multiple bonds contain higher electron densities that repel more than single bonds.
Which of the following correctly describes the bond angle in a molecule of the general type ABx?
The angle between two adjacent A-B bonds
Which of the following are closely related to the electron configuration of an element? Select all that apply.
The chemical behavior of a given element The type of ion formed by a given element The physical properties of an element
As the boiling point graph shows, H2O, NH3, and HF deviate from the boiling point trend shown for the hydrides of the carbon group. Select the statement that correctly explains this deviation.
The hydrogen bonding between molecules of H2O, NH3, and HF is much stronger than the intermolecular forces between CH4 molecules.
Select all the statements that correctly describe the bonding and geometry in the polyatomic ion SeCl5-.
There are 6 electron domains around the central atom. The molecular geometry is square pyramidal. There is one lone pair on the central atom.
Which of the following options interpret the electron configuration 1s22s22p3 correctly? Select all that apply.
There are two electrons in the 1s sublevel. The two electrons in the 2s sublevel have opposite spin. The electrons in the 2p orbitals might be spinning either clockwise or counterclockwise.
True or false: Dispersion forces are exhibited by both polar and nonpolar molecules.
True
True or false: When using VSEPR theory to determine molecular shape, a triple bond counts as a single electron domain even though it consists of 3 shared electron pairs.
True
Which of the following statements correctly describe the format used to represent an ionic compound? Select all that apply.
-The number of atoms/ions in the formula is indicated by a subscript. -Subscripts in the formula for an ionic compound are always reduced to the simplest ratio. -In the formula of an ionic compound the cation is always placed first.
Consider the formation of an ionic bond between the elements potassium (K) and chlorine (Cl). Which of the following statements describe this process correctly? Select all that apply.
-The total number of electrons lost equals the total number of electrons gained. -K loses one electron from its 4s orbital to form a K+ cation. -Both the K+ and Cl- ions have full outer shells containing 8 electrons.
The Lewis structure for one of the resonance forms of the sulfate ion, SO42-, is shown. What is the approximate value of the marked O-S-O bond angle?
109.5o
Calculate the correct number of moles AND formula units in 7.3 x 10-3 g of CaSO4. Avogadro's number is 6.022 × 1023.
5.4 × 10-5 moles of CaSO4 3.2 × 1019 formula units of CaSO4
Which of the following equations will give the correct formula mass of the compound Fe(ClO4)2?
55.85 + 2(35.45) + 8(16.00)
What is the total number of electrons shared between two atoms in a triple bond?
6
The Lewis structure for the AsF5 is shown. The approximate value of the bond angle marked "a" is equal to _____ while the approximate value of the bond angle marked "b" is equal to _____. (Remember that this species has a three-dimensional shape, as indicated by the wedged and dashed bonds.)
90o, 120o
Which of the following structures ARE valid resonance forms for the molecule sulfur dioxide (SO2)? Select all that apply. Note that formal charges have not been included in the given structures.
A D
Select all the options that correctly describe the bond angles associated with each electron-domain geometry.
A bond angle of 180o is observed for a linear system. The trigonal bipyramidal system has two different bond angles. A species with 3 electron domains will exhibit an ideal bond angle of 120o.
Which of the following statements correctly describe hydrates? Select all that apply.
A hydrate is named using a Greek prefix to indicate the number of water molecules per unit. Heating a hydrate can remove some or all of the water molecules from the compound. A hydrate contains a specific number of water molecules per formula unit of compound.
Which of the following statements correctly defines a free radical?
A species with an odd number of valence electrons
Which of the following elements exhibit an irregular filling pattern of the orbitals? Select all that apply.
Ag Cr Cu
Which of the following molecules have a central atom with an incomplete octet? Select all that apply.
AlH3 BF3
Which of the following statements correctly reflects the most important consequence of Pauli's exclusion principle?
An atomic orbital can hold a maximum of two electrons as long as they have opposite spins.
Select all the statements that correctly describe how to draw a Lewis structure.
An electron is added to the total count for each negative charge on the species. A single bond contains 2 electrons and is represented by a solid line. A Lewis structure includes all the valence electrons in the species.
Which of the following molecules have a central atom with an incomplete octet? Select all that apply.
BH3 BeCl2
Why is BeF2 a nonpolar molecule?
BeF2 is linear and therefore the individual bond dipoles cancel to give no net dipole.
Which of the following options correctly describe the structure shown? Select all that apply.
C1 will have a tetrahedral geometry. C2 will have a linear geometry. The bond angles around C2 are approximately equal to 180°.
Which of the following groups contains elements that are chemically similar to each other because they have the same valence-electron configuration? Select all that apply.
Halogens Alkali metals Noble gases
CH3OH
Hydrogen bonding
CaCl2
Ionic bonding
Which of the following options correctly describe a polyatomic ion? Select all that apply.
The atoms of a polyatomic ion are held together by covalent bonds. The charge on a polyatomic ion belongs to the whole unit.
Consider the formula for the ionic compound Na2O. Which of the following statements correctly interpret this formula? Select all that apply.
The compound contains 2 Na+ ions for every O2- ion. The cation in this compound is Na+.
anions
The ion charge is calculated by subtracting 8 from the last digit of the group number.
Draw the Lewis structure for NO2 and select the correct statements about the structure. Select all that apply.
The molecule gives rise to two equivalent resonance structures. There are 17 valence electrons in NO2. The unpaired electron is placed on nitrogen.
Which of the following statements correctly describe how to name a binary molecular compound? Select all that apply.
The second element is named with its root and the suffix -ide. The name of the first element remains unchanged, except for the addition of a prefix where appropriate. A Greek numerical prefix is used to indicate the number of atoms of each element in the compound.
Which of the following would cause the central atom in a Lewis structure to have less than a full octet of electrons? Select all that apply.
The total number of valence electrons is odd. The species has a shortage of valence electrons.
Acetic acid has the formula C2H4O2, while ribose has the formula C5H10O5. Select the statements that correctly describe both the empirical formulas of these compounds and their percent composition by mass.
The two compounds have the same empirical formula. The two compounds have the same percent composition by mass of their elements.
True or false: Both the empirical formula mass (CH) and the molecular formula mass (C6H6) of the hydrocarbon benzene would yield the same mass percent of hydrogen.
True
Without using the periodic table, which of the following correctly represent the electron configuration of an element with 35 electrons? Select all that apply.
[Ar]4s23d104p5 1s22s22p63s23p64s23d104p5
What is the correct ground-state electron configuration for Mo?
[Kr]5s14d5
Select the correct condensed electron configuration for the element S (Z = 16).
[Ne]3s23p4
Calculate the formal charges on each of the nitrogen atoms in the N3- ion shown. The overall charge of the ion has been omitted in the structure.
a = -1; b = +1; c = -1
Oxygen (O2) and ozone (O3) are two different forms of elemental oxygen that occur naturally. Two or more distinct forms of a given element are known collectively as ______.
allotropes
When naming a molecular compound, the number of _________ of each element is indicated by a Greek numerical prefix. The first element in the name is numbered only when more than ____________ atom of that element is present.
atoms 1
In an ABx molecule, the angle between two adjacent A-B bonds is called the
bond electron
The length of a covalent bond is the distance between the
centers
The electron ____________ of an element shows the distribution of electrons within the electronic energy levels of the atom.
configuration
The electron-domain geometry of a species is the arrangement of electron __________________ around the central atom, whereas the molecular geometry is the arrangement of bonded _________________. Two species with the same electron-domain geometry may have different molecular geometries.
domains atoms
The nuclear charge an electron actually experiences is called the ______________ nuclear charge (Zeff). This charge is always ____________ than the actual nuclear charge since in a many-electron system the electrons ______________ each other from the nucleus.
effective less shield
The relative ability of a bonded atom to attract shared electron pairs is called its ___________________. This ability generally _______________ as the size of the atom decreases, since for a smaller atom the shared electrons will be closer to the nucleus.
electronegativity increases
The strength of dispersion forces between two species depends on the mobility of their
electrons polarized stronger
Degenerate orbitals are equal to each other in ______.
energy
A momentary change in the electron density surrounding an atom or a molecule causes it to have a(n)
instantaneous dispersion
The bond typically observed when a metal bonds to a nonmetal is the _____ bond. The metal atom _____ one or more valence electrons while the nonmetal _____ electrons.
ionic; loses; gains
180o
linear
Molecular shape is determined by the number of electron domains around a central atom, where an electron domain may be a(n) electron pair or any between two atoms.
lone bond
When drawing an orbital diagram, orbitals of _____ energy are filled first. By convention, the _____ electron in a given orbital is designated as ↑ and the direction of the arrow indicates the electron _____.
lower; first; spin
The molar mass of a monatomic element is the numerical value listed on the periodic table expressed in units of g/ _________________. For example, the molar mass of calcium (Ca) is __________________ with units of g/______________. (Remember to round to four significant digits.)
mol 40.08 mol
When two polar molecules are close together, the partial positive charge on one molecule will attract the partial charge on the other. This type of intermolecular force is called a - attraction.
negative dipole dipole
The oxoacid of the nitrate ion is called _____ while that of the nitrite ion is called ______.
nitric acid; nitrous acid
When a hydrogen atom is covalently bonded to either oxygen, , or fluorine there will be an attraction between that hydrogen and a lone pair of on a nitrogen, oxygen, or fluorine atom on an adjacent molecule. This attraction is called a bond.
nitrogen electrons hydrogen
Which of the following is the correct name for the molecular compound NO2?
nitrogen dioxide
Dispersion forces are the only type of intermolecular force exhibited by atoms and by molecules. Without the existence of dispersion forces, such substances would only exist as .
nonpolar gases
x
number of terminal atoms
90
octahedral
The ______________ rule states that when atoms bond they may lose, gain, or _______________ electrons in order to attain an outer level containing eight electrons.
octet share
Atoms bond in order to attain a full ______________ level or shell of electrons. Elements in period 2 seek a total of ________________ such electrons while period 1 elements such as hydrogen seek a total of ____________________.
outer 8 2
A bond between two atoms whose electronegativity values differ anywhere from 0.5 to 2.0 is considered ______; whereas a bond between atoms whose electronegativities differ by 2.0 or more is considered ______.
polar covalent, ionic
A unit that contains two or more atoms covalently bonded together but that has an overall charge is called a(n) _____ ion. Many _____ compounds contain such units.
polyatomic; ionic
Ethyne, ethene, and ethane are all hydrocarbons; that is, binary compounds of carbon and hydrogen. In ethyne, C combines with H in a mass ratio of 12:1. In ethene, C combines with H in a mass ratio of 12:2. In ethane, C combines with H in a mass ratio of 12:3. This pattern demonstrates ______.
the law of multiple proportions
120o
trigonal planar
The law of multiple proportions states that if two elements can combine with each other to form two or more different compounds, the ratio of masses of one element that combine with a fixed mass of the other element can be expressed in small ______________ number.
whole
The law of multiple proportions states that if two elements can combine with each other to form two or more different compounds, the ratio of masses of one element that combine with a fixed mass of the other element can be expressed in small ___________________ numbers.
whole
When more than one skeletal arrangement of atoms is possible in a Lewis structure, formal charges can help determine the best arrangement. For molecules, a Lewis structure in which all of the formal charges are ______ is preferred to one that contains ______ formal charges.
zero, nonzero
A compound consists of atoms of __________ or more different ________ that are chemically bonded together.
2 elements
Which of the following provides the correct mathematical operation to calculate the number of molecules in 2.0 mol of CH4?
2.0 mol × 6.022 × 1023 molecules/mol
Which of the following statements correctly describe how to determine the charge of a monatomic ion using the periodic table? Select all that apply.
-Zn always forms the Zn2+ ion. -Elements that form cations in Groups 1 and 2 form ions with a charge equal to the group number. -The charge of most transition metal cations cannot readily be predicted from the periodic table.
Which of the following statements correctly describe effective nuclear charge (Zeff)? Select all that apply.
A lower Zeff makes a given electron easier to remove. Effective nuclear charge is lowered by electron-electron repulsions.
Which of the following elements may form an expanded valence shell? Select all that apply.
Cl Xe S
Which molecule(s) contain(s) an odd number of valence electrons? Select all that apply.
ClO2 NO2 O2-
NO2 SCl6 BeF2
Fewer than eight valence electrons due to an odd number of valence electrons More than eight valence electrons due to an expanded octet Fewer than eight valence electrons due to a shortage of valence electrons
Which of the following statements correctly describe how to name an ionic compound? Select all that apply.
For a monatomic anion, the element name is changed to end in -ide. The cation is named first and the anion second.
Which of the following options correctly reflect the relationship between dispersion forces and particle size? Select all that apply.
For molecules of similar shape, dispersion forces tend to increase with increasing molar mass. Larger particles are more polarizable and experience stronger dispersion forces.
Which of the following options correctly describe the general trends in electronegativity? Select all that apply.
Metals tend to have lower electronegativities than nonmetals. Electronegativity tends to decrease down a group of the periodic table. Fluorine is the most electronegative element.
Which of the following statements correctly describe how to place electrons in orbitals of the same sublevel? Select all that apply.
One electron must be placed in each orbital of equal (degenerate) energy before electrons are paired up. All unpaired electrons in a sublevel should have parallel spins.
Which of the following options correctly describe the shielding effects in a many-electron system? Select all that apply.
Shielding reduces the magnitude of the nuclear charge a given electron experiences. The shielding effect increases with an increasing number of electrons in a given sublevel. Inner electrons are more effective at shielding outer electrons than electrons in the same level.
Which of the following statements correctly describe the general characteristics of a covalent bond? Select all that apply.
The covalent bond involves the attraction between the nucleus of each atom and the electrons of the other. A covalent bond involves the sharing of electrons between two atoms.
